I agree with the post about the x100 (bayer) versus the xtrans sensor being very comparable in terms of noise at 3200.

I shoot raw exclusively and I believe the bayer sensor gives more natural colours and is easier to manipulate in post and I think much of the superiority claimed for the xtrans can be attributed to its bigger file size.

At 6400 the xtrans has better noise characteristics compared to my full frame canon at the same ISO but the image quality is not good enough for me.

I use the xtrans at 3200 as my upper ISO limit in most cases. At lower iso settings such as 1600 or lower I will use the Canon because the image quality is better.

I am saying this based on a lot of work at public events and meetings. When I choose to work with the xpro it is because of the fast lenses which allow acceptable shutter speeds NOT because of the high iso image quality. Shooting jpg is not a serious option - not enough headroom for editing.